Metal spar or girder for aircraft



E. E. BROWN,

MEI/IL SPAR 0R GIRDER FOR MCH/m.

APPLICATION FILED JAN.

I//l TlI/ESS TOHII/E IS EDWARD EUGENE BROWN, OF S'lREATHAM, LONDON, ENGLAND.

METALSPAIR OR GIRDER FOR AIRCRAFT.

Specification of Letters Patent.

Patented Een. 1r, 1920.

Application led IIl'anuary 26, 1918. Serial No. 213,981.

To all w/wm t may concern:

Be it known that I, EDWARD EUGENE BROWN, a subject of the King of England, and a resident of Strea-tham, London, S. WV., England, have invented new and Improved Metal Spars or Girders for Aircraft, of which the following is a full, clear, and eX- act description.

llhis invention is` for improvements in girders or the like for aircraft and has for its object to provide a girder which may be lighter relatively to its strength and stiflness than is the case with those at present in use, such additional stiffness being obtained by embossing the web of the girder, that is to say, forming a hollow rib on one side by pressing the metal forward from the other side. lt has been proposed to provide the Web of a girder with a hollow embossed rib Which rib extended in a continuous curve starting from one end of the girder close to one of the side flanges, extending down at the middle of the girder to the other side flange' and returning again at the opposite end of the girderto the first side flange.

This embossed rib was only intended to receive half of a reinforcing tube which was flanged and riveted to the web by its flanges. rlhe present invention has in view a different arrangement of embossed hollow ribs and no reinforcing tubes therein are employed.

According to this invention a metal girder or the like for aircraft comprising a member of channel-section is characterized by a series of embossed stiffening-ribs formed on the web of the girder and disposed at an angle of not more than 45D to lines transverse to the girder and at right angles to the longitudinal direction thereof.

The stiffening-ribs may be V-shaped and arranged with their limbs extending from top to bottom of the web'obliquely to the flanges, or with the points of the Vs meeting the points of inverted V shaped ribs along a line midway of the depth of the web.

Another feature of this invention consists in a metal girder or the like for aircraft comprising a channel member having-a plate inserted between the flanges of the channel,vv

which plate is embossed to provide ribs which stillen it in the direction in which the stressesfof thegirder tend to bend or break the latterJ lies against the web, is secured thereto by rivets and has. outwardly eXtendedges which are secured to, or engage inturned edges of the flanges to stiffen the flanges.

Additional objects 0f the invention will appear in the following specification in which the preferred form of my invention is described. y

In the drawings similar reference characters refer to similar parts in all the views, in which Figure l is a sectional view on the line 1 1 of Fig. 2.

Fig. 2 is a side elevation of Fig. l.

Fig. 3 is a sectionalgview of a girder constructed according to another means of carrying out this invention and on the line Fig. 4 is a side elevation of Fig. 3.

Fig. 5 is a sectional view of a girder constructed of two channel members, one of which is shown on the line 5 5 of Fig. 4.

Fig. 6 is a sectional view on the line 6 6 of Fig. 5.

F ig. 7 is an elevation of a girder constructed according to a means of carrying out this invention which is the reverse to that shown in Figs. 3 and 4.

Fig. 8 is a transverse section through a girder constructed accordingV to still another means of carrying out this invention; and

Fig. 9 is a perspective view of part of a channel member illustrating a modified detail of construction.

The metal girder comprises a member of channel section having a web A and flanges A1 whereof the edges may be turned over for stilfening as shown at A2. The web A is embossed to provide V shaped ribs B, B1 whose limbs B and B1 lie diagonally to the direction of length of the girder and of a girder thus tend to stiffen the same against deflec-l tion or breakage. The ribs are embossed so that a ridge is formed along the lines indicated at B2, the sides of which may slope at equal angles to each other down to the body of the web in a. straight line or curved as may be desired. A triangular boss C may also be provided in the portions between the two Vs, one only being shown in the drawings.

t will be seen that with this construction any stress tending to bend the girder at right angles to its length must pass through the ridge of one of the stiffening ribs, and thus the girder is strengthened by this embossing. It will be observed that the ribs aov rise abruptly from the level of the web at each end to a maiXimum height which 1s then maintained throughout their length.

bosses D3 are formed in the center of each diamond space inclosed by the ribs.

If desired, two of these girders with ribs shaped as shown in Fig. 2 or in Fig. 4 may be placed back to back as shown in Figs. 5 and 6 and secured together by rivets or spot-welding. Then so used, the ribs on one channel member are staggered relatively to those on the other, as shown in Fig. 5, to further increase the resistance to deflection or breakage.

It will be seen that either of these constructions afford ample room for riveting or spot-welding in the spaces D4.

In the construction shown in Fig. 7, the fiat portions E of the web are made diamond-shaped, the parts E1 E2 between them being the embossed portions of the web. In this case, therefore, it is the limbs of the V-shaped flats at the bottom of the web that meet midway up the web the limbs of corresponding inverted V-shaped flats.

In some cases it may be preferred to provide the embossed yribs on a separate plate instead of on the web ofthe channel member. Such a construction is shown in Fig. 8 where the channel member comprises a web F with an upper flangel F1 and a lower flange F2, the outer edges of the flanges be- .ing turned over at F3. A separate plate G Y ribbed in any desired manner is inserted between the flanges F1 and F2, the edges of the plate being turned outward at G1 and u1.

t0 butt against the inturned edges Fa of the flanges and thus stiflen the flanges. The plate G is secured by rivets II to the web F and the parts G1 may be either merely butted as described to strengthen the lianges F1, F2, or they may be shaped to receive rivets at their ends for securing them to the flanges.

Obviously two of the girders constructed according to Fig. 8 may be placed back to back and secured together if desired. `It will also be understood that where two girders are used back to back, they may be spaced apart by distance-pieces either in the form of blocks or in the form of an open frame as may be convenient.

If desired, the turned-over edges of the flanges of the channel members may be wired. Such an arrangement is shown in Fig. 9 where the lia-nge J is turned over at J1 around awire K. To make this serviceable, the wire must be prevented from slipping relatively to the channel member when stress is put upon the latter. Such slipping may be prevented either 'by clenching the wire at dil'erent points asby indenting the edge in the manner shown at J1, or it may be spot-welded at various points or otherwise secured as found convenient.

It has been proposed to build up composite girders of corrugated plates laid upon each other, the corrugations of one plate lying f at right angles to those of another, such plates being bonded together by various means.

It has also been proposed to form raised ribs on the web of a rolled girder, the ribs being formed in the solid material by rolling and arranged to cross each other after the manner of a latticework with diamondshaped fiat portions between them, but this is not embossing according to the present specification, by which the raising of the metal from one side is intended so that a hollow rib results. Instead of the diamondshaped flat portions, the web was sometimes perforated so that diamond-shaped or claim as new and desire to secure by Letters Patent;

' 1. A girder having a member with a rib extending obliquely longitudinally of the member and back and forth with its limbs disposed at angles to its adjacent limbs, the sides of the rib at the junction of the limbs' being' continuous and extending inwardly to the body ofthe member.

2. A girder having a web with a plurality of V shaped stiffening ribs disposed side by side with both sidesv of each terminal of the limbs of the V shaped stili'ening ribs communicating with the sides of terminals of limbs of adjacent V shaped stiiiening ribs.

3. A girderv having a web with an integral V shaped stiffening rib and an integral boss with sides substantially parallel with the V shaped stiifening rib and inclosed thereby.

4. A girder having' aweb with two series of V shaped ribs, oneseries inverted relatively to the other, the points of one series of V shaped ribs meeting the points of the other series of V shaped ribs intermediate the sides of the web.

5. A girder having a web with two series of V shaped embossed ribs, one series inverted relatively to the other, the points of one series of V shaped ribs meeting the points of the other series of V shaped ribs intermediate the sides of the web.

6. A girder having a web with two series No' claim is made in this speci-A bossed ribs and spaced therefrom.

7. A gi-rder having two webs, each with two series of V shaped ribs, and with one series inverted relatively to the other, with the points of one series meeting the points of the other series, the two webs being secured together with the V shaped ribs on one web staggered relatively to the V shaped ribs on the other web. i

8. A of V girder having a web with two series shaped ohannels, one series being 1nverted relatively tothe other and with the points of.one series of V shaped channels meeting the points of the other series of V shaped channels. 1

9. In a girder, a channel member having a web, and flanges disposed at angles to the web, a member with a stifening groove disposed between the lianges and secured to,v

the web and flanges on the second mentioned member disposed at the first mentioned flanges at points spaced from the web.

l0. A girder having a member with a 'rib extending obliquely. longitudinally of the member and back and forth with its limbs disposed at angles to adjacent parts, and fianges at the sides of the member disposed at angles to the body of the member.

1l'. A girder having a member with a rib extending' obliquely longitudinally of the member and back and forth with its limbs disposed at angles to adjacent limbs, the rib at the sides of the member extending inwardly to the body of the member, and flanges at the sides of the member extending at an angle to the body of the member.

12. A girder having a member with a rib extending obliquely longitudinally of the member and back and forth with its limbs disposed at angles to adjacent limbs, the sides ofthe rib at the junction of the limbs being continuous, disposed at the sides of the member and extending inwardly to the body of the member.

13. A girder having a member with an integral rib on oneA face and extending obliquely longitudinally of the member and back and forth with its limbs disposed at angles to adjacent limbs.

14. In a girder, a channel member having a web and flanges disposed at angles to the web, a member with a stiffening groove disposed between the anges and secured to the web adjacent the ianges, and flanges on the second mentioned member disposed at the flanges on the channel member.

EDWARD EUGENE BROWN. 

